Vehicle attitude stabilization and control system

ABSTRACT

A system for stabilizing and controlling the attitude of a vehicle with respect to the underlying terrain when stationary by means of double acting jacks including means for pressure equalization therebetween is disclosed. Electrical control circuitry providing means for fully automatic leveling including a novel pendulum actuated electrical switch is described. Novel jack means particularly adapted for use in the system and preferred electrical control circuitry are disclosed.

United States Patent Eranosian I 1 June 13, I972 [54] VEHICLE ATTITUDESTABILIZATION AND CONTROL SYSTEM [72] Inventor: John Erlnosian, 175Phillips Road, Woodside, Calif, 94062 [22] Filed: Dec. 14,1970

(21] Appl.No.: 97,774

Marlowe ..254/1 22 X 2,l32.343 l0/l938 Jarrett 2,229,530 l/l 941 South254/86 H 3,289,868 l2/l966 Miller et a! .m254/45 X 3,350,063 10/1967Thurlow. Sr. et al ..2$4/86 H X Primary Examiner-Othell M. SimpsonAttorney-Mellin. Moore & Weissenberger [5 7] ABSTRACT A system forstabilizing and controlling the attitude ofa vehicle with respect to theunderlying terrain when stationary by means of double acting jacksincluding means for pressure equalization therebetween is disclosed.Electrical control circuitry providing means for fully automaticleveling including a novel pendulum actuated electrical switch isdescribed. Novel 56] References Cited ack means particularly adapted foruse In the system and UNITED STATES PATENTS preferred electrical controlcircuitry are disclosed. 2,029,179 l/l936 Marlowe ..254/l22 8 Chins,lllDrawlng Figures l H 2| --u U fl |l I PATENTEUJUH 1 3 m2 SHEET 1!]? 2INVENTOR. JOHN ERANOSIAN My r- W 6%, ATTORNEYS VEHICLE ATTITUDESTABILIZATION AND CONTROL SYSTEM BACKGROUND OF THE INVENTION Thisinvention relates to the stabilization and control of the attitude ofvehicles when stationary with respect to the underlying terrain and moreparticularly to a system including double acting jacks adapted to extendbetween the underside of such vehicles and such terrain under thecontrol of electrical circuitry including an automatic leveling means.

It is common practice to stabilize vehicles such as trailers and camperswhen stationary with respect to the underlying terrain by means ofadjustable jacks, usually located at corners of the vehicle, in order toavoid unpleasant swaying and jiggling of the vehicle when used as livingquarters. Such jacks may also be used to control the attitude of thevehicle with respect to the underlying terrain in order to level thevehicle on uneven terrain or raise a portion of the vehicle with respectto the terrain for maintenance purposes. In general, such jacks havebeen individually and manually operated to obtain the desired attitudeand stability, and often they are separate from the vehicle, thusrequiring manual placement between the vehicle and the underlyingterrain.

It is known in the prior art to provide systems for the attitude controlof vehicles with respect to the underlying terrain when stationary thatare integral with the vehicle and power operated under remote control.However, such systems have not been suitable for use with alreadyexisting vehicles, but instead have required design changes and thesacrifice of usable space in the vehicle to accommodate the system.

It is an object of this invention to provide a system for the attitudecontrol and stabilization of vehicles with respect to the underlyingterrain when stationary that is power operated under remote control andmay be mounted on existing vehi cles with minimum modification in orsacrifice of the usable space in the vehicle.

It is known in the prior art to utilize gravity responsive means such asa pendulum or mercury switch to provide automatic leveling of thevehicle by remote control of the system. US. Pat. No. 2,510,6l to Twistand US. Pat. No. 3,164,275 to Schatzl et al. are representative of suchprior art systems, for example. However, such systems have accomplishedautomatic leveling at the expense of stabilization since the gravityresponsive means thereof merely selects and actuates the jack or jackscorresponding to the lowest portion of the vehicle, leaving the jack orjacks corresponding to the highest portion of the vehicle out of contactwith the underlying terrain. It will be understood that the jacks of thesystem must be reliably retracted sufficiently to avoid any contactwhatever with the underlying terrain while the vehicle is in motion.Thus, when the vehicle is stationary it is necessary to lower the jacksinto contact with the terrain before any leveling or stabilization maybe accomplished. If all of the jacks are lowered simultaneously andequally, it may be possible to stabilize the vehicle on even terrain butno leveling can be accomplished, and if the terrain is uneven it willalso be impossible to accomplish any stabilization.

If the system is adapted to automatically lower only the jack or jackscorresponding to the lowest portion of the vehicle, as in the prior art,it may be possible to level the vehicle, but the vehicle will not bestabilized since the system will not lower one or more of the jacks ofthe system into contact with the terrain.

US. Pat. No. 3,43l,727 to Grumman is representative ofa semi-automaticsystem known in the prior art which is capable of achieving bothstabilization and leveling by manipulation of controls. However,according to the teaching of this patent, manual control is required tofirst level the vehicle along one of the axes thereof and then level thevehicle along the other of the axes thereof.

It is a further object of the invention to provide a system capable offully automatic leveling of a vehicle when stationary and at the sametime stabilizing such vehicle in its level position.

It is another object of this invention to provide an electrical controlfor use in a fully automatic leveling and stabilization system, whichcontrol may be mounted at any desired point on the vehicle and adjustedto actuate any one jack of the system individually, and any two adjacentjacks of the system simultaneously, in order to provide fully automaticleveling of the vehicle.

SUMMARY OF THE INVENTION Briefly, the system of this invention forleveling and stabilizing a vehicle having a longitudinal axis and atransverse axis comprises a source of pressurized fluid mounted on thevehicle, a first hydraulic jack means mounted on the vehicle and adaptedto be lowered into contact with the underlying terrain connected to saidsource of pressurized fluid through a first electrically actuated,four-way valve and a second hydraulic jack means mounted on the vehicleand adapted to be lowered into contact with the underlying terrainconnected to said source of pressurized fluid through a secondelectrically actuated four-way valve, the first and second hydraulicjack means being mounted on a line parallel to one axis of the vehicleand on opposite sides of the other axis of the vehicle. The systemincludes electrical control circuitry comprising first normally openmanual switch means for simultaneously actuating both four-way valves tolower both jack means, second normally open manual switch means forsimultaneously actuating both four-way valves to raise both jack means,automatic means for actuating each four-way valve individually and bothfour-way valves simultaneously to lower the jack means, and normallyopen switch means for actuating said automatic means. The automaticmeans preferably includes an electrical switch comprising a pendulummember having an external circular elec' trical contact surface thereoncentrally suspended in the plane of a pair of spaced coplanar electricalcontacts insulated from each other and each having a concave surfaceadjacent the pendulum defining equal portions of a 180 arc of a circleconcentric with and having slightly larger diameter than the diameter ofthe circular electrical contact surface of said pendulum member, theswitch being oriented such that the diameter of the circle through theends of the I arc is parallel to one axis of the vehicle, the spacebetween the coplanar contacts is centered on a radius of the circlewhich is parallel to the other axis of the vehicle and the plane of theco-planar electrical contacts is parallel with the plane of the floor ofthe vehicle. The preferred embodiment includes four jack means, onelocated at each corner of the vehicle with the first manual switchcontrol means adapted to simultaneously lower the pair of jack means onone side of the longitudinal axis of the vehicle independently of thepair of jack means on the other side of the longitudinal axis of thevehicle and the second manual switch control means adapted to raise allof the jack means simultaneously.

DESCRIPTION OF THE DRAWING The foregoing and other objects and featuresof the subject invention will be more fully understood from thefollowing detailed description when read in conjunction with the drawingwherein:

FIG. I is a perspective view of a trailer type vehicle on which thesystem of the invention may be used with advantage;

FIG. 2 is a plan view of the vehicle of FIG. I with elements of oneembodiment of the system of this invention indicated schematically;

FIG. 3 is a plan view of the vehicle of FIG. I with the elements ofanother embodiment of the system of this invention indicatedschematically;

FIG. 4 is a fragmentary view in elevation showing a preferred jack meansfor use in the system of this invention in a lowered position;

FIG. 5 is a fragmentary view in elevation of the jack means of FIG. 4 inthe raised and locked position;

FIG. 6 is an enlarged fragmentary view in perspective showing structuraldetails of the preferred jack means for use in the system of thisinvention;

FIG. 7 is an enlarged cross-sectional view taken along line 7-7 of FIG.6;

FIG. 8 is a cross-sectional view of the pendulum actuated electricalcontrol means preferred for use in the system of this invention;

FIG. 9 is a cross-sectional view taken along lines 99 of FIG. 8', and

FIG. I is a schematic representation of the electrical and hydrauliccircuitry of the system in accordance with the preferred embodiment ofthis invention.

DETAILED DESCRIPTION It will be understood that this invention may beused in connection with any type of vehicle in order to stabilize andcontrol the attitude of such vehicle with respect to the underlyingterrain when stationary. By definition, a vehicle is adapted to move,and such movement normally occurs in a direction parallel to one of theaxes of the vehicle except when turning. The axis along which thevehicle moves will be referred to as the longitudinal axis of thevehicle hereinafter, and the axis of the vehicle perpendicular to thelongitudinal axis in the plane thereof will be referred to as thetransverse axis of the vehicle. It will be understood that the system ofthis invention is utilized only when the vehicle is stationary, and thuswhen the vehicle is in motion all elements of the system are retractedand securely rendered inoperative.

Referring to FIG. I, a vehicle in connection with which the system ofthis invention may be used with particular advantage is shown inperspective. The vehicle shown is a house trailer I0 comprising a livingcompartment or body 12 having a floor, walls and roof and provided witha door I4 and windows 15 as appropriate. The body [2 is mounted formovement on its longitudinal axis by means of wheels 16 journaled at theends of axles extending parallel to the transverse axis of the body 12.As shown in FIGSv 1-3, a pair of wheels is mounted on each side of thelongitudinal axis of the body 12. However, many house trailers utilize asingle wheel on each side of the longitudinal axis where the weight ofthe house trailer 10 is low, and it is of course possible to utilize asingle wheel located on a longitudinal axis of the trailer. Furthermore,it will be understood that the system of this invention is applicable toa body similar to the body 12 but adapted to be carried on the bed ofatruck such as the well-known camper bodies which are widely used withpick-up trucks, for example.

It will be understood that the body 12 is mounted on the wheels I6through an appropriate spring means to reduce the effect of bumps andjolts (incurred while moving) on the contents of the body 12. The body12, as shown in FIG. I, is provided with a tongue 17 by means of whichit is connected to the towing vehicle. When disconnected from the towingvehicle, it is customary to support the tongue 17 with respect to theunderlying terrain by means ofa manually operated jack, as indicated at18, which jack 18 is usually provided with a wheel for contacting theterrain in order to enable the body to be moved when disconnected fromthe towing vehicle. It is of course possible to level the longitudinalaxis of the body 12 by appropriate manual adjustment of the jack 18.However, the springs by which the body 12 is mounted on the wheels 16cause such leveling to be unstable at best. In addition, such springsenable the body to sway and jiggle in response to any change in thedistribution of weight within the body, and in fact even wind blowingagainst the exterior can cause unpleasant swaying due to the resilienceof the springs. Furthermore, the attitude of the transverse axis of thebody is established by the underlying terrain upon which the wheels l6rest.

As shown in FIG. 1-3, the body 12 may be both stabilized and leveled bymeans of a plurality of jacks 20 extending between the bottom of thebody 12 and the underlying terrain.

For example, four jacks 20 may be utilized, as shown in FIGS. 1 and 2,one at each of the respective corners of the body I2. By properadjustment of such jacks 20 with respect to each other, both thelongitudinal and transverse axes of the body 12 may be leveled, and inaddition the weight of the body may be taken off the springs by whichthe body is mounted on the wheels I6 to thereby stabilize the body 12 inits level position. However, it will be understood that leveling andstabilization of the body 12 might be accomplished through the use ofonly two jacks located on opposite sides of the longitudinal axis of thebody and both being on the opposite side of the axle (by which the bodyis mounted on the wheels I6) from the tongue 17 (by which the body istowed), as shown in solid lines in FIG. 3. Successful leveling andstabilization of the body [2 would require that the jack means l8associated with the tongue I7 be manually adjusted to raise the tongueend of the body 12 above the other end of the body 12 so that when thejacks 20 are subsequently adjusted to provide leveling of thelongitudinal and transverse axes of the body I2, the weight thereofwould be removed from the wheels I6 and distributed evenly among thejacks l8 and the jacks 20. All of the above has heretofore beenaccomplished in the prior art through the use of jacks which arestructurally independent of the body 12 and which have been manuallyplaced between the body 12 and the underlying terrain and manuallyadjusted in order to obtain the desired stabilization and leveling.Similarly, jack means capable of accomplishing the above ends have beenbuilt into bodies such as trailer body I2 at the sacrifice of usablespace within the body 12. However, a reliable jack unit capable of beingeasily and permanently installed on a wide variety of trailer bodies hasnot previously been available.

According to applicants invention, a jack unit is provided comprising apair of scissors jacks 20 each operated by a different double-actinghydraulic ram 21 and mounted at opposite ends of a tubular beam 22 ofheavy-gauge metal. As best shown in FIGS. 4, 5, and 6, each scissorsjack comprises a first pair of lever arms 23 pivoted at one of theirends about a pin 24 extending through the end of the tubular metallicbeam 22. A second pair of lever arms 25 are pivoted about a pin 26,which is slidably received in a pair of slots 27 in opposite sides ofthe tubular metallic beam 22. Corresponding lever arms 23-25 of thepairs of lever arms are picotally connected to each other intermediatetheir ends by means of a pin 28 which passes through both pairs of leverarms. Thus, when the pin 26 is caused to slide within the slot 27 towardthe pin 24, the lever arms 23-25 of respective pairs pivot about thepins 24, 26, and 28 so that the ends thereof move away from the beam 22in the manner well known in the art. As shown in the figures, twofurther pairs of lever arms 29 pivoted in the free ends of the pairsoflever arms 23-25 by means of pins 30 and 31 and having their free endspivoted about a common pin 32 are provided. A foot or bearing member 33is also pivoted about the pin 32, and springs 34 are connected betweenopposite sides of the foot 33 and the pins 30 and 31, respectively, toinsure that the foot 33 always presents its bearing surface in properorientation to effectively engage the underlying terrain. It will beunderstood that the scissors jack 20 may include additional stages oflever anns in order to increase the length by which the jack 20 may beextended. Similarly, more lever arms might be used in achieving a givenamount of extension in order to reduce the length of such lever arms andprovide greater structural rigidity.

As shown in FIG. 7, the tubular metallic beam 22 may be square incross-section and may be affixed to the underside of the floor of thebody l2 by any suitable means such as, for example, by straps 35 weldedthereto. Since the beam 22 is a rigid member, the straps 35 may bebolted to spaced frame members or the underside of the body I2. The beamlength and strap spacing may be adjusted to suit the particular body 12involved. Thus, it will be seen that the jack unit of the system inaccordance with the teaching of this invention may be easily and quicklymounted on existing bodies without sacrifice of usable space above thefloor of the body 12.

As also shown in FIG. 7, the double-acting rams 21 which operate thejacks are contained within the tubular metallic beam member 22. It willbe understood that the cylinder of the ram 21 is firmly fastened to thetubular beam member by any appropriate means (not shown) and that thepiston rod 36 of 5 the hydraulic ram extends along the longitudinal axisof the tubular beam 22 into operative connection with the pin 26 of thescissors jack 20. Thus, the extension and retraction of the piston rod36 of the hydraulic ram 21 forces the pin 26 to slide within the slots27 toward and away from the pin 24, thereby extending and retracting thejack 20. To avoid wear on the pin 26 and slots 27 in use, the pin 26 issupported by a rectangular sleeve 26a slidably received within the beammember 22.

As best shown in FIG. 5, the scissors jack 20 may be firmly and reliablyheld in its fully retracted position by means of a rod 37 adapted toextend through apertures in spaced bracket members 38, 39 and under thepin 31 when the jack 20 is in its fully retracted position. Thus, thejack 20 will be prevented from extending into contact with theunderlying terrain should the hydraulic pressure in the ram 21associated therewith decrease while the vehicle is in motion. It is ofcourse necessary to remove the rod 37 prior to actuating the ram 21 todrive the jack 20 into contact with the ground in order to avoid damageto the rod 37. When the vehicle is stationary and the jack 20 is inengagement with the underlying terrain, the rod 37 may be allowed tohang loosely in bracket 38 so as to be readily available for manualinsertion under the pin 31 and in the apertures of the brackets 38, 39when the jack 20 is retracted for movement ofthe vehicle.

As indicated in FIG. 10, all of the hydraulic rams 21 utilized in thesystem are connected to a common source of pressurized fluid, asindicated by fluid pump 40 and reservoir 41 arrangement. Each of therams 21 is coupled to the pump 40 and reservoir 41 through a differentfour-way hydraulic valve 42. Four-way hydraulic valves of many types arewell known in the prior art. Such valves include appropriate fluidpassageways and mechanical valving elements whereby the pressurizedfluid from the pump 40 may be connected to either side of the piston ofthe hydraulic ram 21, with the other side of the piston of the hydraulicram 21 being connected to the reservoir 41. In its normal position, thefour-way valve, of course, seals both sides of the piston from eachother and from the pump and reservoir, thereby enabling the piston ofthe hydraulic ram to be maintained in a selected position. Theutilization of hydraulic rams to drive the jacks 20 from a common sourceof pressurized fluid, in accordance with the teaching of this invention,is particularly advantageous since such a system is inherentlyself-equalizing in terms of the force exerted by each ofthe jacks 20 onthe underlying terrain. Such self-equalizing characteristic is anessential feature of a system in accordance with the teaching of thisinvention because it insures that all of the jacks 20 will be in contactwith the underlying terrain and exerting equal force before theautomatic leveling of the vehicle is commenced.

It will be understood that if any two jacks 20 of a system in accordancewith this invention are simultaneously lowered into contact with theunderlying terrain and such underlying terrain is uneven, the downwardmotion of the first of such jacks 20 to engage the underlying terrainwill cease upon engagement until the other jack means has also engagedthe underlying terrain. This is due to the fact that any force developedby the first jack means 20 upon engagement with the underlying terrainwill be immediately transferred to the second jack means through thehydraulic system. When both jack means are in engagement with theunderlying terrain, the force due to the pressurized fluid will beevenly distributed between them so that the vehicle can be raised withrespect to the underlying terrain. The force equalization among thevarious jacks, when operated simultaneously, is an important aspect ofapplicants invention. It will be understood that other means ofactuating the jacks, such as reversible motors, cannot be used in placeof the double-acting hydraulic rams in the system of applicant'sinvention unless an appropriate means is included in the system forequalizing the forces generated by the jack means upon initialengagement with the underlying terrain.

It will be understood that, according to the teaching of this invention,each of the hydraulic rams 21 may be actuated independently of theothers. The four-way valves 42 are normally closed so that a particularram will not be connected to the source of pressurized fluid andreservoir unless the fourway valve associated therewith is actuated.Thus, it is possible to exert unequal forces among the various jacks 20of the system in order to accomplish leveling of the vehicle. Accordingto the teaching of this invention, it is also possible to subsequentlyequalize the forces among the various jacks of the system withoutdestroying the leveling which has been previously accomplished.

According to the preferred embodiment of this invention, the four-wayvalves 42 of the system are solenoid-actuated, thus enabling electricalcontrol of the system. The electrical control of the system isparticularly desirable in connection with the automatic leveling featureof the subject application, since it enables the physical location ofthe various mechanical elements of the system at any point on thevehicle body as convenient or desired. Thus, the four-way valves 42 neednot be physically located adjacent the respective rams 21, as suggestedby the schematic representation of the system shown in FIG. 10. Instead,the four-way valves may all be physically located in close proximity tothe pump 40 and reservoir 41, for example, and appropriate hydrauliclines and electrical wires interconnecting the elements of the systemmay be mounted on or under the floor of the vehicle body 12 or on theroof and walls, as convenient and desired.

Referring to FIGS. 8 and 9, a pendulum-actuated electrical switchstructure 49 particularly suited for providing automatic leveling actionin a system in accordance with this invention is shown. The switchcomprises a base 50 which may be of any suitable material, such as metalor plastic, for example, a tu bular body 51 of insulating material, anda cap 52 of insulating material. One end of the tubular insulating body51 is sealed to the base 50, as by means of a resilient O-ring 53, forexample, and the cap 52 is fitted into the other end of the tubularinsulating body 51. The switch 49 is adapted to be mounted with thelongitudinal axis of the tubular insulating body 51 in a verticalposition. A pendulum member 54 is suspended within the tubularinsulating body 51 from the cap 52, preferably along such longitudinalaxis. The pendulum member 54 comprises a heavy mass having a circularelectrically conductive surface on the exterior thereof and is suspendedfrom the cap 52 in a manner to enable the mass to swing in anydirection. For example, the mass 54 may conveniently comprise a solidmetallic cylinder suspended within the tubular insulating body 51 bymeans of an electrically conductive wire 55 extending between one of itsends and the cap 52. The wire 55 may extend through the cap 52 and ismounted therein by an appropriate insert 56 so that electricalconnections may be made to the mass 54. A plurality of metallicelectrical contact members 61, 62, 63, and 64 are insulatingly mountedon the base 53 within the tubular insulating member 51 and spaced fromeach other about the periphery of the mass 54. As shown in FIG. 9, eachof the contact members 61-64 provide an arcuate surface adjacent theelectrically conducting exterior surface of the mass 54. The contactsare arranged with respect to each other such that the arcuate surfaceseach form an arc of a common circle which is concentric with thecircular electrically conducting surface on the exterior of the mass 54and which has a diameter slightly larger than the diameter of thecircular electrically conducting surface on the mass 54. The contactmembers 61-64 may be conveniently mounted on the base 53 by means of adielectric ring 57, for example, which is appropriately bonded to thebase 53. A plurality of electrically conductive rods 65, 66, 67, and 68,each associated with a different one of the contact members 61-64,extend through the insulating cap 52 and into electrical connection withthe contact members 61-64 associated therewith. In addition to providingmeans for making an electrical connection between elements of the systemand the contact members 61-64, the conductive rods 65-68 aremechanically attached to the base 50 and may each have a nut 59 threadedthereon in contact with the insulating cap 52. By selective adjustmentof the nut 59 associated with each of the rods 65-68, the longitudinalaxis of the tubular body 51 may be adjusted with respect to the base 50by varying the amount of compression on the resilient O-ring 53 atvarious points about its periphery. Thus, it will be seen that therelationship between the circular electrically conductive surface on theexterior of the mass 54 and the circle formed by the arcuate innersurfaces of the contact members 61-64 may be adjusted by adjusting thelongitudinal axis of the tubular body 51 with respect to the base 50.

It will be seen that if the base 50 of the switch 49 is mounted on aflat surface of the vehicle body 12 which it is desired to level, thenthe longitudinal axis of the body 51 is, or can be easily adjusted tobe, perpendicular to such flat surface. If the flat surface is notlevel, then the mass 54 of the pendulum will swing into contact with oneof the electrical contact means 61-64, establishing an electricalconnection between the electrically conductive surface on the exteriorof the mass 54 and the electrically conductive inner surface of thecontact means 61-64. In fact, it is possible for the electricallyconductive exterior surface of the mass 54 to contact any two adjacentones of the contact means 61-64 due to the spacing between such contactmembers. It will be understood that ordinarily the circular exteriorsurface of the mass 54 would swing into contact with the circular innersurface of a contact member at a single point. However, where suchsingle point of contact between the circular exterior surface of themass 54 and the circle of which the interior surface of the contactmembers 61-64 are apart would occur at the space between adjacentcontact members, then two points of contact will result, one betweeneach of the adjacent contact members and the circular exterior surfaceof the mass 54. lt has been found that the amount of spacing between thecontact members 61-64 in order to provide the desired two-point contactunder these conditions is not critical. Similarly. it has been foundthat the relative diameter of the circular exterior surface of the mass54 and the circle of which the interior surfaces of the contact members6l-64 are a part is not critical in this regard. However, such relativediameter does determine the precision with which leveling may beobtained through the use of the switch 49. It will be understood thatthe greatest precision in leveling will be obtained where the differencebetween such diameters is made as small as is practical.

Referring to FIG. 2, it will be seen that, in the preferred embodimentof the system in accordance with this invention, four jack means areused and the switch 49 is provided with four contact members 61-64, eachadapted to electrically actuate a different one of the jacks 20, asindicated by the arrows. According to this embodiment of the invention,the jacks 20 are located at the corners of the body 12 of the vehicle,and each of the contact members 61-64 has a circular inner surfaceforming an arc of substantially 90 of the circle of which they each forma part. The switch 49 is positioned so that opposite spaces between thecontact members lie on the lines parallel to the longitudinal andtransverse axes, respectively, of the vehicle. As will be more fullyexplained hereinafter, the switch 49 is connected into the electricalcontrol circuitry of the system such that when the mass 54 thereofswings into contact with one of the contact members 61-64, it willactuate the jack 20 associated therewith, causing the jack to elevateits associated corner of the vehicle body 12. Thus, if the rear of thevehicle body 12 is lower than the forward part thereof, the mass 54 willtend to swing into contact with that contact member, 61, for example,corresponding to the lowest rear corner, thereby actuating the jacklocated at such comer. As the jack extends, raising the associatedcorner of the vehicle, the mass 54 will tend to roll or slide along thecircular inner surface of the contact member 61 until it reaches thespace between the contact member 61 and the contact member 62.

The mass 54 will then make electrical contact with both contact members61 and 62, actuating both jacks simultaneously and raising the rear ofthe vehicle until it is level with the forward portion of the vehicle,at which point the mass 54 will swing away from both contact memberssimultaneously.

As shown in FIG. 8, the tubular body 51 may be filled with an insulatingoil 60. Such insulating oil will tend to damp any tendency of the mass54 to oscillate or swing back and forth between contact members inoperation. Such insulating oil will also inhibit any arcs that mighttend to form in air between the mass 54 and a contact member due to theclose spacing and electrical potential difference therebetween.

Referring to P16. 3, it will be seen that the system of this inventionmay utilize a single pair of jacks 20, one located on each side of thelongitudinal axis of the vehicle and rearwardly of the transverse axisthereof. In this embodiment of the invention, the switch 49 wouldinclude but two contact members 61 and 62, and the spacing therebetweenwould lie on a line parallel to such longitudinal axis. As pointed outhereinabove, the jack means 18 associated with the tongue 17 of thevehicle would be used to raise the front of the vehicle body 12 abovethe rear portion thereof. This would cause mass 54 to swing into contactwith one or both of the contact members 61-62 as described above,actuating the jacks 20 to raise the rear of the vehicle body 12 to alevel position of the vehicle body 12. As described in connection withthe embodiment shown in FIG. 2, the inner surfaces of the contactmembers 61-62 form arcs of a circle. lt will be understood thataccording to the embodiment shown in solid lines in FIG. 3, automaticleveling of the vehicle body 12 can only occur where the rear of suchbody 12 is lower than its forward portion. This system could be modifiedto provide fully automatic leveling by the addition ofa single furtherjack 20, located on the longitudinal axis, as indicated in dotted lines,in which case a third electrical contact member would be included in theswitch 49', which third electrical contact member would be provided withan inner surface forming substantially of the circle of which the innersurfaces of contact members 61 and 62 are a part. The third contactmember would be spaced from contact members 61-62 with such spaces lyingon a line parallel with the transverse axis of the vehicle body 12.However, such three-jack system would not be as stable as the embodimentshown in FIG. 2 and would be more expensive than the embodiment shown insolid lines in FIG. 3 and therefore is not favored in accordance withthe teaching of this invention.

Referring to FIG. 10, the preferred embodiment of the system inaccordance with the teaching of this invention, including the electricaland hydraulic circuitry, is shown schematically. For ease ofunderstanding, reference numerals of the other drawings of thisapplication have been used wherever possible in FIG. 10 to indicatecorresponding elements of the system. As shown in H6. 10, the systemincludes a first jack unit comprising a pair of scissors jacks 20a and20b mounted at opposite ends of tubular metallic beam 220 and a secondjack unit comprising a pair of scissors jacks 20c and 20d mounted atopposite ends of tubular metallic beam 22b Each of the scissors jacksZoo-20d is operated by a different one of double-acting hydraulic rams2111-2 1d. As indicated by dotted lines, the hydraulic rams 21a and 21!)are mounted within tubular metallic beam member 22a, and hydraulic rams21c and 21d are mounted within tubular metallic beam 2212. Each of thehydraulic rams 21a-21d is connected to the fluid pump 40 and reservoir41 through a different one of four-way valves 42a-42b. According to thepreferred embodiment of this invention, such four-way valves arenormally closed, providing a seal between opposite sides of the pistonof the hydraulic ram associated therewith and between such ram and thepump 40 and reservoir 41. Each of the four-way valves 420-42 includes afirst solenoid 43a-43d which, when properly energized by connectionacross an appropriate source of electrical energy such as batter 45,will cause the mechanism of its associated four-way valve to connect theopposite sides of the piston of the associated hydraulic ram to the pump40 and reservoir 41 in such a way as to cause the piston rod 36 thereofto be retracted into the cylinder, thereby raising the associated jacka-20d. A second solenoid 44a44d associated with each of the four-wayvalves 420-42d when connected across battery 45 will cause the mechanismof the four-way valve associated therewith to connect opposite sides ofthe piston of the associated hydraulic ram to the pump 40 and reservoir41 in such a way as to cause the piston rod 36 to extend from thecylinder thereof, thereby extending the associated jack 20a-20d. Theelectrical control system of the preferred embodiment of the system inaccordance with the teaching of this invention includes a triple-throw,double-pole switch 46 and a triple-throw, three-pole switch 47 as wellas a solenoid actuated motor control switch 48 and the pendulum actuatedlevel control switch 49, as described hereinabove. Switches 46 and 47are spring loaded to cause them to normally assume a position in whichthe movable switch contact thereof rests on a contact which isunconnected to any other element of the system. Thus, switches 46 and 47are normally open" switches. The movable contacts of both switches aredirectly connected to one side of the battery 45. The other side of thebattery 45 is connected to one side of the motor 40, to one side ofsolenoids 43a-43d, to one side of solenoids 440-44, and to one side ofthe solenoid of the solenoid-actuated motor control switch 48. Two ofthe contacts of one wafer of switch 46 and two of the contacts of onewafer of switch 47 are electrically connected to the opposite side ofthesolenoid of the solenoid-actuated motor control switch 48 from thebattery 45. Thus, if the movable contact of either switch 46 or switch47 is thrown to a contact other than the one on which it normally rests,the solenoid-actuated motor control switch 48 will be energized causingthe pump 40 to be connected across the battery 45, thereby pumpinghydraulic fluid from the reservoir 41 and providing pressurized fluidfor the operation of the hydraulic rams Zia-21d under the control offour-way valves 42a-42d.

One contact of the other wafer of switch 46 is connected to the otherside of solenoids 43a-43d from the battery so that when the movablecontact of such wafer is thrown to this contact, each of the solenoids43a-43d will be connected across the battery 45, thereby actuating thefour-way valves 42a-42d in such a way as to cause the jacks 20a-20d tobe retracted. The other contact of this wafer of switch 46 is connectedto the circular electrically conductive surface of the pendulum mass 54of leveling switch 49 through the wire 55. It will be seen that contactmembers 61-64 are connected to the opposite sides of solenoids 44a-44d,respectively, from the battery 45 through the conductive rods 65-68,respectively. Thus. if the movable contact of this wafer of switch 46 isthrown to this contact, the leveling switch 49 is connected into thecircuit and is capable of actuating any one of the four-way valves420-424 or any two adjacent ones of such valves by engagement betweenthe circular conductive surface on the mass 54 and the appropriatecontact member or members 61-64 under the influence of gravity. Sincethe movable contacts of switch 46 are ganged together. as indicated bythe dotted line, the pump 40 will be actuated whenever the switch 46 isthrown to a contact other than the normally open contact.

Similarly, two of the contacts of the switch 47 are connected to theopposite side of the solenoid of the solenoidoperated motor controlswitch 48 from the battery, and the movable contacts of all three wafersof the switch 47 are ganged together, as indicated by the dotted line,so that the pump 40 will be actuated when the switch 47 is thrown to acontact other than the normally open contact. One contact of the secondwafer of switch 47 is connected to the opposite side of solenoid 44afrom the battery 45, and the corresponding contact of the third wafer ofswitch 47 is connected to the opposite side of solenoid 44d from thebattery 45. Similarly, the other contact of the second wafer of switch47 is connected to the opposite side of solenoid 4417 from the battery45, and the corresponding contact of the third wafer of switch 47 isconnected to the opposite side of solenoid 44c from the battery 45.Thus, when the movable contact of switch 47 is thrown to one of thecontacts other than the normally open contact, jacks 20a and 20d will beextended by actuation of four-way valves 42a and 42d, which willsimultaneously connect the rams 21a and 21d to the pump 40 and reservoir4]. When the movable contact of switch 47 is thrown to the secondcontact other than the normally open contact, solenoids 44b and 44c willbe connected across battery 45, actuating four-way valves 42b and 42c toconnect rams 21b and 210 to pump 40 and reservoir 41 in such a way as toextend jacks 20b and 200. Since, according to the preferred embodimentof this invention, the beams 22a and 22b of the jack units are mountedwith their longitudinal axes parallel to the transverse axis of thevehicle, operation of switch 47 as described above will enable eitherside of the vehicle to be raised independently of the other so that thewheels and tires may be serviced. it will be understood that switch 47could be adapted to actuate all four jacks 20a-20d simultaneously, inwhich case the switch 47 could be replaced by a double-throw, doublepoleswitch. However, it is believed that the added feature of enablingservicing of the wheels and tires of the vehicle on which the system isused is of sufficient value to justify the relatively small additionalexpense of enabling jacks 20a and 20d to be operated independentlyofjacks 20b and 20c to raise the side of the vehicle associatedtherewith. It will be understood that an appropriate check valve couldbe used, one with each of four-way valves 420-4211, in order to avoidthe tendency of the jacks 20a-20d to slump over a period of time due tothe leakage of hydraulic fluid from one side of the piston to the otherof the rams 210-2 ld through the associated four-way valves 42a-42d.

In accordance with the teaching of this invention, the primary purposeof switch 47 is to provide stabilization of the vehicle, and the primarypurpose of switch 46 is to provide leveling of the vehicle. Thus, whenthe vehicle is stationary and it is desired to level the vehicle andstabilize it in its level position, switches 46 and 47 are bothutilized. Ordinarily switch 47 would be utilized first and, inaccordance with the preferred embodiment, the jacks 20a and 20d on oneside of the vehicle would be lowered into engagement with the underlyingterrain by manual operation of the switch 47, appropriate engagement andforce equalization between the jacks 20a and 20d being indicated when aslight lifting of the corresponding side of the vehicle is detected. Theswitch 47 is then manually operated to lower the other two jacks 20b and20c into engagement with the underlying terrain, and again appropriateengagement and force equalization is detected by a slight lifting of theassociated side of the vehicle, at which time the switch 47 is allowedto return to its normally open position. The switch 46 is then manuallyoperated to connect the leveling switch 49 into the control circuit. Theswitch 49 will operate as described hereinabove to level the vehicle.The completion of the leveling operation will be indicated when furthermovement of the vehicle ceases, and the switch 46 will then be allowedto return to its normally open position. At this point, switch 47 may bemanually switched to each of its positions other than the normally openposition momentarily in order to insure force equalization among thejacks 200-2011 of the system. It will of course be understood thatswitch 46 could be operated first to provide leveling through theengagement of one and possibly two of the jacks 20a-20d with theunderlying terrain. Switch 47 would then be operated in order to bringthe remaining jacks into engagement with the underlying terrain and toobtain the desired force equalization among the jacks 20a-20d.

Thus, it will be seen that the vehicle stabilization and control systemin accordance with the teaching of this invention enables automaticleveling and stabilization of a vehicle by remote control. Such systemin its preferred embodiment is also adapted to enable portions of thevehicle to be raised with respect to the underlying terrain in order toprovide for the maintenance of the vehicle. The system may be easilymounted on any existing vehicle with minimum sacrifice of usable spaceand maximum flexibility in physical location of the elements of thesystem. It will be understood that the pendulum-actuated level controlswitch 49 may be mounted in any suitable location on the vehicle so longas it is mounted with proper orientation with respect to thelongitudinal and transverse axes of the vehicle. Similarly, theelectrical and hydraulic elements of the system may be physicallylocated as desired and interconnected with other elements of the systemthrough electrical wiring and hydraulic conduits.

Double acting hydraulic rams are used in the preferred embodimentdescribed hereinabove in order to provide positive hydraulic retractionof the jack means. However, this is not essential to my invention, andsingle acting hydraulic rams may be used with spring means to return thejacks to their retracted position upon release of the hydraulicpressure. Although it is possible that the jacks may occasionally offersufficient re sistance to retraction to overcome the spring force (i.e.,stick") the hydraulic system would be simplified in that twoway valveswould be used in place of four-way valves. The spring means mayconveniently comprise helical tension springs each disposed about a ramand connected at one end to the beam member 21 and at the other end tothe pin 26 or bearing member 26a so that the spring is placed in tensionwhen the associated jack means is lowered hydraulically by connectingpressurized fluid from the pump 40 to the ram through the two-way valve.When the two-way valve returns to its normal position, it willdisconnect the ram from the pump 40 and maintain the ram in its extendedposition. Actuation of the two-way valve in its opposite sense willconnect the ram to the reservoir 4i, allowing the spring tension todrive the hydraulic fluid from the ram and retract the jack means.

It will be understood that the only change required in the electricalcontrol circuit where solenoid actuated two-way valves and single actingrams with spring return are used in the system is to omit the electricalactuation of the pump 40 during retraction of the jack means.

Other embodiments of my invention will be obvious to those skilled inthe art.

What is claimed is:

l. in a system for stabilizing and leveling a stationary vehicle havinga longitudinal axis and a transverse axis; a source of pressurized fluidmounted on said vehicle; a first hydraulic jack means mounted on saidvehicle and adapted to be lowered into engagement with the underlyingterrain hydraulically connected to said source of pressurized fluidthrough a first electrically actuated valve; a second hydraulic jackmeans mounted on said vehicle and adapted to be lowered into engagementwith the underlying terrain hydraulically connected to said source ofpressurized fluid through a second electrically actuated valve; saidfirst and second jack means being mounted on opposite sides of one ofsaid axes of said vehicle and on the same side of the other of said axesof said vehicle; and electrical control circuitry comprising firstnormally open manual switch means for simultaneously actuating both ofsaid valves to lower both of said jack means into engagement with theunderlying terrain; second normally open manual switch means forsimultaneously actuating both of said valves to raise both of said jackmeans; automatic means for actuating each of said valves individuallyand both of said valves simultaneously to lower said jack means; andthird normally open manual switch means for actuating said automaticmeans.

2. In a system as claimed in claim 1, third and fourth hydraulic jackmeans mounted on said vehicle and adapted to be lowered into contactwith the underlying terrain hydraulically connected to said source ofpressurized fluid through third and fourth electrically actuated valves,respectively; said third and fourth jack means being mounted on oppositesides of said one of said axes of said vehicle from each other and onthe opposite side of said other of said axes of said vehicle from saidfirst and second jack means; said first normally open manual switchmeans being adapted to simultaneously actuate said third and fourthvalves to lower said third and fourth jack means into engagement withthe underlying terrain independently of said first and second jackmeans; said second normally open manual switch means being adapted toactuate said third and fourth valves simultaneously with said first andsecond valves to simultaneously raise all of said jack means; and saidautomatic means being adapted to actuate any one of said valvesindependently and any two adjacent valves simultaneously to lower saidjack means associated therewith.

3. The system as claimed in claim 1 wherein said first and second jackmeans are mounted on opposite sides of said lon gitudinal axis of saidvehicle and on the same side of said transverse axis of said vehicle.

4. The system as claimed in claim 2 wherein said first and second jackmeans are mounted on opposite sides of said transverse axis of saidvehicle on one side of the longitudinal axis thereof and said third andfourth jack means are mounted on opposite sides of said transverse axisof said vehicle on the other side of the longitudinal axis thereof.

5. The system as claimed in claim 4 wherein said jack means are locatedwith respect to each other such that lines drawn therebetween innumerical order form a rectangle.

6. The system as claimed in claim 1 wherein said first and secondhydraulic jack means each comprise a scissors jack structure actuated bya hydraulic ram and wherein said first and second jack means are mountedat opposite ends of a tubular metallic beam member with said hydraulicrams housed within said beam member.

7. The system as claimed in claim I wherein said automatic meansincludes a pendulum actuated electrical switch comprising a pendulummember having an external circular elec trical contact surface of givendiameter thereon, a pair of spaced electrical contact members insulatedfrom each other and having coplanar concave conducting surfaces definingequal portions of an arc of substantially l of a circle having adiameter slightly larger than said given diameter, means suspending saidpendulum member with said circular electrical contact surface thereon inthe plane of said conducting surfaces of said contact members from apoint concentric with said circle, said pendulum actuated switch beingoriented such that the diameter of said circle passing through the endsof said arc of said circle formed by said conducting surfaces of saidcontact members is perpendicular to said one axis of said vehicle, thespace between adjacent ends of said conducting surfaces on said contactmembers is centered on a radius of said circle which is parallel to saidone axis of said vehicle, and the plane in which said conductingsurfaces of said contact members are coplanar is parallel to a selectedgenerally horizontal surface of said vehicle to be leveled.

8. A jack unit comprising a tubular metallic beam; a pair of hydraulicrams having their cylinders rigidly mounted within said tubular metallicbeam co-axially thereof, the piston rod of each of said rams beingadapted to project from the cylinder thereof along the axis of saidtubular metallic beam and toward a different end thereof, said beamhaving a pair of opposed slots through the wall thereof at each end; apair of scissors jacks each mounted at a different end of said beam,said scissors jacks each comprising a first pair of lever arms pivotedabout a first pin fixedly mounted in the associated end of such beam,and a second pair of lever arms pivoted about a pin received in saidpair of opposed slots at the associated end of said beam, said pistonrod of each of said rams being mechanically connected to the one of saidsecond pins at the end of said beam toward which said piston rodprojects and each of said lever arms of said first pair of lever armsbeing pivotally connected to a different one of said second pair ofleverarms.

i t a a t

1. In a system for stabilizing and leveling a stationary vehicle havinga longitudinal axis and a transverse axis; a source of pressurized fluidmounted on said vehicle; a first hydraulic jack means mounted on saidvehicle and adapted to be lowered into engagement with the underlyingterrain hydraulically connected to said source of pressurized fluidthrough a first electrically actuated valve; a second hydraulic jackmeans mounted on said vehicle and adapted to be lowered into engagementwith the underlying terrain hydraulically connected to said source ofpressurized fluid through a second electrically actuated valve; saidfirst and second jack means being mounted on opposite sides of one ofsaid axes of said vehicle and on the same side of the other of said axesof said vehicle; and electrical control circuitry comprising firstnormally open manual switch means for simultaneously actuating both ofsaid valves to lower both of said jack means into engageMent with theunderlying terrain; second normally open manual switch means forsimultaneously actuating both of said valves to raise both of said jackmeans; automatic means for actuating each of said valves individuallyand both of said valves simultaneously to lower said jack means; andthird normally open manual switch means for actuating said automaticmeans.
 2. In a system as claimed in claim 1, third and fourth hydraulicjack means mounted on said vehicle and adapted to be lowered intocontact with the underlying terrain hydraulically connected to saidsource of pressurized fluid through third and fourth electricallyactuated valves, respectively; said third and fourth jack means beingmounted on opposite sides of said one of said axes of said vehicle fromeach other and on the opposite side of said other of said axes of saidvehicle from said first and second jack means; said first normally openmanual switch means being adapted to simultaneously actuate said thirdand fourth valves to lower said third and fourth jack means intoengagement with the underlying terrain independently of said first andsecond jack means; said second normally open manual switch means beingadapted to actuate said third and fourth valves simultaneously with saidfirst and second valves to simultaneously raise all of said jack means;and said automatic means being adapted to actuate any one of said valvesindependently and any two adjacent valves simultaneously to lower saidjack means associated therewith.
 3. The system as claimed in claim 1wherein said first and second jack means are mounted on opposite sidesof said longitudinal axis of said vehicle and on the same side of saidtransverse axis of said vehicle.
 4. The system as claimed in claim 2wherein said first and second jack means are mounted on opposite sidesof said transverse axis of said vehicle on one side of the longitudinalaxis thereof and said third and fourth jack means are mounted onopposite sides of said transverse axis of said vehicle on the other sideof the longitudinal axis thereof.
 5. The system as claimed in claim 4wherein said jack means are located with respect to each other such thatlines drawn therebetween in numerical order form a rectangle.
 6. Thesystem as claimed in claim 1 wherein said first and second hydraulicjack means each comprise a scissors jack structure actuated by ahydraulic ram and wherein said first and second jack means are mountedat opposite ends of a tubular metallic beam member with said hydraulicrams housed within said beam member.
 7. The system as claimed in claim 1wherein said automatic means includes a pendulum actuated electricalswitch comprising a pendulum member having an external circularelectrical contact surface of given diameter thereon, a pair of spacedelectrical contact members insulated from each other and having coplanarconcave conducting surfaces defining equal portions of an arc ofsubstantially 180* of a circle having a diameter slightly larger thansaid given diameter, means suspending said pendulum member with saidcircular electrical contact surface thereon in the plane of saidconducting surfaces of said contact members from a point concentric withsaid circle, said pendulum actuated switch being oriented such that thediameter of said circle passing through the ends of said 180* arc ofsaid circle formed by said conducting surfaces of said contact membersis perpendicular to said one axis of said vehicle, the space betweenadjacent ends of said conducting surfaces on said contact members iscentered on a radius of said circle which is parallel to said one axisof said vehicle, and the plane in which said conducting surfaces of saidcontact members are coplanar is parallel to a selected generallyhorizontal surface of said vehicle to be leveled.
 8. A jack unitcomprising a tubular metallic beam; a pair of hydraulic rams havingtheir cylinders rigidly mounted within said tubular metallic beamco-axially thereoF, the piston rod of each of said rams being adapted toproject from the cylinder thereof along the axis of said tubularmetallic beam and toward a different end thereof, said beam having apair of opposed slots through the wall thereof at each end; a pair ofscissors jacks each mounted at a different end of said beam, saidscissors jacks each comprising a first pair of lever arms pivoted abouta first pin fixedly mounted in the associated end of such beam, and asecond pair of lever arms pivoted about a pin received in said pair ofopposed slots at the associated end of said beam, said piston rod ofeach of said rams being mechanically connected to the one of said secondpins at the end of said beam toward which said piston rod projects andeach of said lever arms of said first pair of lever arms being pivotallyconnected to a different one of said second pair of lever arms.